In our daily environments, the modern electronic devices such as smart phones, smart watches or imaging apparatus usually have to be implanted with new functions for improving the quality of life and living. For examples, the new functions include gesture control, motion sensitive elements, 3D identification and/or image extraction quality enhancement. While multiple functions are integrated into the electronic device, the reduction of the overall volume is still and should be taken into consideration. Moreover, in addition to the portable and movable capability, electric power consumption is also an important factor for the electronic device with the multiple functions. In case that the power consumption is high, the electronic device is not favored by the user. Moreover, among these new functions, a corresponding lighting device is usually necessary. The lighting area of the lighting device has to cover the motion area or the imaging range. In response to the change of the application scenario, the corresponding motion area is generally changed. If the lighting area is not correspondingly adjusted at this moment, the image extraction quality is possibly deteriorated (e.g., the lighting area is reduced) or the power consumption is increased (e.g., the lighting area is increased). Moreover, since all devices are operated independently, the operating method is complicated to the user and becomes hindrance of using the electronic device. Consequently, the conventional technology needs to be further improved. In pursuit of the optical performance enhancement, the power consumption and the user friendliness are important factors in developing the system.